High-power-plasma PECVD of SiNx and Al2O3 for industrial solar cell manufacturing

Excellent surface passivation is a key feature of high-efficiency c-Si solar cell concepts. Manz AG in collaboration with Fraunhofer ISE has developed a high-power-plasma (HPP) vertical plasma-enhanced chemical vapour deposition (PECVD) system that allows the preparation of excellently passivating hydrogenated amorphous silicon nitride (SiNx) and aluminium oxide (Al2O3) films at high deposition rates, leading to a throughput of about 1200 wafers per hour for one deposited film at a small footprint of the tool. Double layer SiNx front surface anti-reflection coatings (ARC) were outperforming the reference processes at Fraunhofer ISE. Al2O3 layers reached the same level of passivation compared to the reference PECVD process. Control of carbon and oxygen atoms and the oxidizing gas during the deposition helps to maintain a stable and robust process.